Abstract
Forging dies have to resist high mechanical and thermal loads. Therefore, they are usually nitrided. Former investigations showed that the abrasive wear at the critical parts of the dies is much higher than the nitriding hardness depth. Carbonitriding offers the possibility to increase the hardness depth in shorter treatment times because of the higher treatment temperature. The (carbo-)nitrided surface region obtains a better hardness at elevated temperatures and a better wear resistance than the untreated steel. In order to create a wear- and corrosion-resistant compound layer at the surface, a nitriding process step can be conducted after carbonitriding. The present work deals with developing a carbonitriding treatment for forging dies and investigations on the wear resistance of the created surface zones in model wear tests and tool life time experiments under industrial conditions. The aim of this work was to produce heat- and wear-resistant precipitation layers in hot working tool steels in economical treatment durations.
Highlights
Forging dies are usually used at temperatures above 200 ◦ C
An increase in the carbonitriding temperature is limited by the increasing ammonia decomposition at higher temperatures
In order order to to produce a sufficiently deep surface layer hardened with nitride precipitates and produce a sufficiently deep surface layer hardened with nitride precipitates and at at the the same achieve sufficient sufficient core corestrength, strength,the theheat heattreatment treatment must adapted to the same time time achieve must bebe adapted to the die die material
Summary
Forging dies are usually used at temperatures above 200 ◦ C. The requirements for such tools result from the specific stress and are generally a high tempering and heat resistance, a sufficient wear resistance, a high ductility, a high thermal conductivity, a low hot cracking sensitivity, good sliding properties of the surface, and a low tendency to stick [1]. Nitriding and nitrocarburizing can optimize the wear behavior and the temperature resistance of the tool surface areas [2,3]. The increased tempering resistance and high-temperature strength of the nitrided tool-edge zone compared to the unnitrided material result from the high hardness and residual compressive stresses in the diffusion layer [4]. Nitrided hot working tools are very brittle and tend to crack due to the thermal and mechanical stresses during forging, the average tool life of nitrided tools is about 40% higher than that of tools that have only been quenched and tempered [3,5]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
